For most home TV and cable internet connections, the cable you see is usually a 75-ohm RG6 coaxial cable with an F-type connector. For RF equipment, antennas, radio systems, and test instruments, 50-ohm coaxial cables such as RG58, RG8, or RG213 are also common.
This guide explains what coaxial cable does, what it looks like, the main types of coaxial cable, common sizes, TV and internet use cases, and how coax differs from Ethernet cable.
What Is a Coaxial Cable?
A coaxial cable is a cable built with one central conductor surrounded by insulation, shielding, and an outer jacket. The word “coaxial” means the inner conductor and outer shield share the same axis.
This layered structure helps the cable transmit RF signals while reducing electromagnetic interference. That is why coaxial cable is widely used in applications where signal stability matters, including TV distribution, cable modems, antennas, radio equipment, and measurement systems.
The main parts of a coaxial cable are:
| Part | What It Does |
|---|---|
| Center conductor | Carries the signal |
| Dielectric insulation | Keeps the center conductor separated from the shield |
| Foil or braided shield | Reduces interference and helps contain the signal |
| Outer jacket | Protects the cable from wear, moisture, and handling damage |
| Connector | Connects the cable to a device, wall outlet, antenna, modem, or test instrument |
What Does a Coaxial Cable Do?
A coaxial cable transmits high-frequency electrical signals from one device or network point to another. In everyday use, it may carry TV signals from an antenna, cable signals from a wall outlet to a cable box, or broadband signals from a cable network to a modem.
Common uses include:
| Use Case | Typical Coax Cable |
|---|---|
| Cable TV | RG6 75-ohm coax |
| Satellite TV | RG6 75-ohm coax |
| Cable internet modem | RG6 75-ohm coax |
| TV antenna | RG6 75-ohm coax |
| Older analog video or CCTV | RG59 75-ohm coax |
| Long outdoor TV/cable runs | RG11 75-ohm coax |
| Radio and RF systems | RG58, RG8, RG213, or similar 50-ohm coax |
| Lab and test equipment | 50-ohm coax with BNC, SMA, or N-type connectors |
Coaxial cable is not only a “TV cable.” It is a broader RF cable category used anywhere a shielded transmission line is needed.
What Does a Coax Cable Look Like?
A coax cable is usually a round, relatively stiff cable with a single center conductor inside. For TV and cable internet, it often has a threaded metal F-type connector with a small center pin.
You may see coaxial cable in these places:
| Location | What It Usually Connects |
|---|---|
| Behind a TV | TV, cable box, antenna, or satellite receiver |
| Wall cable outlet | Cable TV or cable internet service |
| Cable modem | Coax from the wall to the modem |
| Outdoor antenna | Antenna to indoor TV equipment |
| CCTV installation | Camera to recorder or monitor |
| RF lab bench | Signal generator, oscilloscope, antenna, or test device |
Coax cable is easy to distinguish from Ethernet cable. Coax is round and usually has one center pin. Ethernet cable usually has a rectangular RJ45 plug with eight small contacts. If you are trying to identify a cable behind a TV or modem, the dedicated guide on what a coax cable looks like gives a more visual checklist.
Common Types of Coaxial Cable
Coaxial cables are often identified by an RG number, impedance, size, shielding, and intended application. RG originally came from older military-style cable designations, but today the term is used broadly in commercial cable naming.
The most common coaxial cable types are listed below. For a deeper comparison of RG6, RG59, RG11, RG58, and 50-ohm vs 75-ohm cable families, use the full types of coaxial cable guide.
| Cable Type | Impedance | Approx. Outer Diameter | Common Use | Key Note |
|---|---|---|---|---|
| RG6 | 75 ohm | 6.9 mm / 0.27 in | Cable TV, satellite, cable internet, antenna | Best common choice for modern home TV and cable modem connections |
| RG59 | 75 ohm | 6.1 mm / 0.24 in | Older analog video, CCTV, short low-frequency runs | Higher loss than RG6 at higher frequencies |
| RG11 | 75 ohm | 10.3 mm / 0.40 in | Long cable TV, satellite, and broadband runs | Lower loss but thicker and less flexible |
| RG58 | 50 ohm | 5.0 mm / 0.20 in | RF, radio, test leads, older thin Ethernet | Flexible and common for short RF connections |
| RG8 | 50 ohm | 10.3 mm / 0.40 in | Amateur radio, RF transmission | Larger and lower loss than RG58 |
| RG213 | 50 ohm | 10.3 mm / 0.40 in | RF transmission, radio systems | Durable 50-ohm RF cable |
| RG174 | 50 ohm | 2.5 mm / 0.10 in | Short internal RF pigtails, small antennas | Very flexible but higher loss |
Cable dimensions vary by manufacturer, jacket material, shielding, and construction. Always check the datasheet when exact diameter, attenuation, or connector fit matters.
RG6 Coaxial Cable
RG6 is the most common coaxial cable for modern residential TV, satellite, antenna, and cable internet connections. It is usually a 75-ohm cable and is commonly terminated with F-type connectors.
Use RG6 when you need a coaxial cable for:
| Application | Why RG6 Fits |
|---|---|
| Cable TV | Standard home cable distribution |
| Cable internet modem | Common cable modem connection from wall outlet to modem |
| Satellite TV | Suitable for high-frequency satellite signals |
| Digital TV antenna | Lower loss than older RG59 in many home runs |
| General home coax wiring | Widely available and compatible with F-type connectors |
For most home users asking “what is the best TV cable wire?” RG6 is the practical answer. For a TV-focused buying guide, see this breakdown of the best coaxial cable for TV, cable box, satellite, and antenna connections.
RG59 Coaxial Cable
RG59 is a 75-ohm coaxial cable historically used for analog video, CCTV, and older TV installations. It is thinner than RG6 and can be easier to route, but it usually has more signal loss at higher frequencies.
RG59 may still be acceptable for short analog video or CCTV runs, but it is usually not the best choice for modern cable internet, satellite TV, or long digital TV runs. If you are replacing or installing cable for TV or internet today, RG6 is usually the better option.
RG11 Coaxial Cable
RG11 is a thicker 75-ohm coaxial cable used when lower signal loss is important over longer distances. It is common in long cable TV, satellite, outdoor, underground, or distribution runs.
The tradeoff is flexibility. RG11 is harder to bend and terminate than RG6, so it is usually used for long backbone runs rather than short patch cables behind a TV or modem.
RG58, RG8, and RG213 Coaxial Cable
RG58, RG8, and RG213 are commonly associated with 50-ohm RF applications. They are used with antennas, radio transmitters, receivers, test instruments, and wireless equipment.
Use these cables when your equipment specifies 50-ohm coax. Do not substitute a 75-ohm TV coax for a 50-ohm RF system unless the equipment documentation says it is acceptable.
50 Ohm vs 75 Ohm Coaxial Cable
The two most common coaxial cable impedances are 50 ohms and 75 ohms. Matching impedance matters because mismatched cables, connectors, and equipment can cause signal reflections, loss, ghosting in video systems, or measurement errors in RF systems.
| Impedance | Common Applications | Typical Cable Types |
|---|---|---|
| 75 ohm | TV, cable TV, satellite, cable internet, video, antennas | RG6, RG59, RG11 |
| 50 ohm | RF, radio, wireless, antennas, test equipment, transmitters | RG58, RG8, RG213, RG174 |
For TV and cable modem use, choose 75-ohm coax. For radio, RF testing, and many antenna systems, choose the 50-ohm cable specified by the equipment.
Coaxial Cable Sizes and Diameter
Coax cable size affects flexibility, connector compatibility, handling, and signal loss. Larger coaxial cables often have lower loss, but they are also less flexible and harder to install.
| Cable Type | Approx. Outer Diameter | Impedance | Typical Use |
|---|---|---|---|
| RG174 | 2.5 mm / 0.10 in | 50 ohm | Small RF pigtails |
| RG58 | 5.0 mm / 0.20 in | 50 ohm | RF, radio, short test cables |
| RG59 | 6.1 mm / 0.24 in | 75 ohm | Older video, CCTV |
| RG6 | 6.9 mm / 0.27 in | 75 ohm | TV, cable internet, satellite |
| RG11 | 10.3 mm / 0.40 in | 75 ohm | Long cable runs |
| RG213 | 10.3 mm / 0.40 in | 50 ohm | RF transmission |
These values are approximate. Quad-shield, plenum-rated, outdoor-rated, direct-burial, or manufacturer-specific versions can differ in diameter. For connector-fit details and a cleaner diameter chart, see the coax cable sizes and diameter chart.
Coaxial Cable for TV and Antenna Connections
Most modern TV, cable box, satellite, and antenna connections use 75-ohm RG6 coaxial cable with F-type connectors. RG6 is preferred over older RG59 for many higher-frequency digital TV, satellite, and broadband applications. For scenario-by-scenario recommendations, use the dedicated guide to the best coaxial cable for TV and antenna connections.
| TV Use Case | Recommended Cable | Connector | Note |
|---|---|---|---|
| Cable TV | RG6 75-ohm | F-type | Most common home TV cable |
| TV antenna | RG6 75-ohm | F-type or region-specific TV connector | Good for digital TV antenna runs |
| Satellite TV | RG6 75-ohm | F-type | Use outdoor-rated cable if exposed |
| Long outdoor run | RG11 75-ohm | F-type | Lower loss over distance |
| Older analog video | RG59 75-ohm | BNC, RCA, or F-type | Often used for legacy CCTV/video |
F-type connectors are widely used for TV, satellite, cable internet, and over-the-air antenna connections. In some regions, IEC-style TV antenna connectors are also common.
Coaxial Cable for Internet
Cable internet service commonly uses coaxial cable to bring broadband RF signals from the wall outlet to a cable modem. After the modem, Ethernet cable or Wi-Fi is usually used to connect computers, routers, switches, access points, and other devices.
A typical home cable internet path looks like this:
Cable provider network -> coax wall outlet -> cable modem -> Ethernet/router/Wi-Fi -> devicesThe coax cable is part of the access connection from the cable provider. Ethernet usually begins after the modem or gateway.
Modern cable broadband systems are based on DOCSIS technology. CableLabs describes DOCSIS 4.0 as supporting up to 10 Gbps downstream capacity and up to 6 Gbps upstream capacity over hybrid fiber-coax networks, although actual service speeds depend on the provider, network, modem, and plan.
Coaxial Cable vs Ethernet Cable
Coaxial cable and Ethernet cable are not the same thing. They may both be used in home internet setups, but they do different jobs.
| Feature | Coaxial Cable | Ethernet Cable |
|---|---|---|
| Common connector | F-type, BNC, SMA, N-type | RJ45 |
| Cable shape | Round, often stiff, single center conductor | Round or flat twisted-pair cable with multiple conductors |
| Typical home use | Wall outlet to cable modem, TV, antenna | Modem/router to computer, switch, access point, smart TV |
| Signal type | RF signals, TV, broadband, antenna, radio | Ethernet network data |
| Common cable names | RG6, RG59, RG11, RG58 | Cat5e, Cat6, Cat6A, Cat7, Cat8 |
If you have cable internet, the coaxial cable usually brings the service into the modem. Ethernet then carries local network traffic from the modem or router to your devices. The separate coaxial cable vs Ethernet cable article explains when you need a cable modem, MoCA adapter, or ordinary Ethernet cable.
Can You Convert Coax to Ethernet?
You cannot convert coaxial cable to Ethernet with a simple passive plug adapter. Coax and Ethernet use different signaling methods, connectors, and equipment requirements.
There are two common ways coax and Ethernet interact:
| Device | What It Does |
|---|---|
| Cable modem | Converts the cable provider’s coax broadband signal into Ethernet and/or Wi-Fi for your home network |
| MoCA adapter | Uses existing in-home coax wiring to create an Ethernet-like network connection between rooms |
A cable modem is used for internet service from a cable provider. A MoCA adapter is used inside a home or building when you want to use existing coaxial wiring as a network path.
What Is a MoCA Adapter?
A MoCA adapter is a device that lets network data run over existing coaxial cable inside a home. MoCA stands for Multimedia over Coax Alliance, the industry group behind the standard.
MoCA adapters are useful when:
| Scenario | Why MoCA Helps |
|---|---|
| You have coax wall outlets but no Ethernet wiring | MoCA can use the existing coax path |
| Wi-Fi is weak in another room | MoCA can provide a wired backhaul |
| You need a more stable link for gaming or streaming | Wired coax networking can reduce reliance on wireless signal quality |
| Pulling new Ethernet cable is difficult | MoCA may avoid opening walls |
MoCA is not the same as a cable modem. A cable modem connects your home to the cable internet provider. MoCA adapters create a local network connection over the coax wiring already inside the home.
How to Choose the Right Coaxial Cable
The right coaxial cable depends on the application, impedance, distance, connector, and environment.
| Need | Recommended Choice |
|---|---|
| Modern TV, cable box, or cable modem | RG6 75-ohm coax with F-type connectors |
| Outdoor antenna or satellite run | Outdoor-rated RG6, or RG11 for long distance |
| Long cable TV or broadband distribution run | RG11 75-ohm coax |
| Older CCTV or analog video | RG59 75-ohm coax may be acceptable |
| RF radio or test equipment | 50-ohm coax specified by the device, such as RG58, RG8, or RG213 |
| Small internal antenna lead | RG174 or another small RF coax, if specified |
| In-home coax-to-network link | MoCA adapters, not a passive coax-to-Ethernet plug |
Before buying, check:
- Required impedance: 50 ohm or 75 ohm
- Connector type: F-type, BNC, SMA, N-type, RCA, or another connector
- Cable length and expected signal loss
- Indoor, outdoor, plenum, or direct-burial rating
- Shielding level, especially near electrical noise
- Device or service provider requirements
Common Mistakes to Avoid
One common mistake is assuming all coaxial cables are interchangeable. A 75-ohm RG6 cable and a 50-ohm RG58 cable may look similar to a non-specialist, but they are meant for different systems.
Another mistake is buying a “coax to Ethernet adapter” expecting it to work like a simple plug converter. For networking, you need active equipment such as a cable modem or MoCA adapter.
It is also common to reuse old RG59 cable for modern cable internet or satellite TV. It may work in some short runs, but RG6 is usually a better choice for current home TV and broadband installations.
FAQ
What is a coaxial cable used for?
A coaxial cable is used to transmit high-frequency signals for cable TV, satellite TV, TV antennas, cable internet, CCTV, radio systems, wireless equipment, and RF test instruments.
What does a coax cable look like?
A coax cable is usually a round cable with a single center conductor. TV and internet coax cables often have a threaded metal F-type connector with a center pin.
Is coaxial cable the same as Ethernet?
No. Coaxial cable carries RF signals and is commonly used for TV, antennas, cable modems, and RF systems. Ethernet cable carries network data between routers, switches, computers, access points, and other network devices.
What type of coaxial cable is used for TV?
Most modern TV, cable box, satellite, and antenna connections use 75-ohm RG6 coaxial cable with F-type connectors.
What type of coaxial cable is used for internet?
Cable internet connections usually use 75-ohm RG6 coaxial cable from the wall outlet to the cable modem. After the modem, Ethernet or Wi-Fi is used for the local network.
Is RG6 better than RG59?
For modern TV, satellite, and cable internet, RG6 is usually better than RG59 because it generally has lower loss at higher frequencies. RG59 is still used in some older analog video and CCTV installations.
What is RG11 used for?
RG11 is used for longer 75-ohm cable runs where lower signal loss is needed. It is thicker and less flexible than RG6, so it is usually used for long runs rather than short patch cables.
What is the difference between 50-ohm and 75-ohm coax?
75-ohm coax is common for TV, video, cable internet, and satellite systems. 50-ohm coax is common for RF, radio, wireless, antenna, and test equipment. The cable impedance should match the equipment.
Can I convert coaxial cable to Ethernet?
Not with a simple passive adapter. A cable modem converts a cable provider’s coax broadband signal to Ethernet or Wi-Fi. MoCA adapters can use existing in-home coax wiring to create a network link between rooms.
What connector does a TV coax cable use?
Most TV, cable box, satellite, and cable modem coax connections use F-type connectors. Some regions and TV antenna systems may also use IEC-style connectors.
Does coax cable size matter?
Yes. Cable size affects flexibility, connector fit, and signal loss. Larger coax cables such as RG11 often have lower loss over long distances, while smaller cables are easier to route but may have higher loss.
